Cap



May 1l, 1948. A, WARTH TAL 2,441,173

, CAP

Filed Dec. 28. 1942 Ubin mm2-17:, 2, Jauz a7;a,u@,.n,

v m MMMMM Patented May 11 ,I 1948 CAP Albin H. Warth and Paul Grabus, Jr., Baltimore, Md., asslgnors to Crown Cork & Seal Company, Inc., Baltimore, Md., a corporation of New York Application December 28, 1942, Serial No. 470,382

seal with the m'outh or lip of a container such as a glass bottle, (3) overcoming objectionable irregularities in the liner surface and the container surface which might produce leakage, (4) eliminating in many instances the necessity of a center spot facing, and (5) offsetting any deciency of the cellulosic cushion liner in resiliency and compressibility.

The foregoing advantages ofthe invention have been established by severe tests of crowns provided with sealing film coated liners in which cases of carbonated goods were inverted, then rolled over` several times one way and then in the reverse direction, then dropped 9" and iinally stored for several weeks. At the end of the tests, all of the bottles showed from 3.48 to 3.53 volumes of gas which was just a little higher than that with the composition cork control liners.

A further object of the invention is to provide a cap having a cushion liner provided with a sealing lm which is thoroughly sanitary and non-toxic, and which moreover gives a nice appearance to the cap, both before application to and after removal from the container.

I An additional object of the invention is to provide a cap having a cellulosic cushion liner coated with a sealing lm which is suiliciently thermoplastic to permit the applidation of a center spot without the necessity of employing an independent adhesive to adhere the spot to the cushion liner. l

Of equal importance with the foregoing is an object of the invention to provide cushion lining material which may be readily prepared from a compressed or densied cellulosicv body, such a pulp board, board composed of wood fibers and cotton fibers, as well as gray cotton board, by dipping strips of suitable ,thlckness into the sealing film solution and forming on the surface of the board a sealing i'llm of the desired depth.

As explained, this sealing i'llm is deposited from Asolution and on drying in the air, or by forced hopper of the automaticcap assembling machine without the necessity of being stacked right side up.

vIn carrying out the invention, cellulosic board of the character above mentioned composed wholly of wood iibers as described in the copending application of Warth, Serial No. 401,852, now abandoned, or the copending application of Costa and Ryan, Serial No. 418,248 now Patent No. 2,338,705 is preferred, but any suitable cellulosic board may be used since the sealing lm of the present invention overcomes effectively any deficiencies in resiliency or compressibility between the board and the usual cork composition. Preferably, the cushion board is approxi-- mately .0505' in thickness, and is' provided with a sealing film byv running the board as an endless band or strip through a bath of the prepared coating material at a slow speed so that the material drains back to prevent any objectionable film characteristics from developing on the board. The coating is thus applied to both sides ofthe board. In the case of a coating for a spot crown, the thickness of the coating is about .0025" for each side. As explained above, it is unnecessary to use a center spot with cushion liners in accordance with the present invention since a coating of approximately .005" for each side may be readily obtained, or even greater thicknesses by subjecting the board to a suitable treatment, such as one or more clippings until the desired thickness of coating is built up. The thickness of the` lm takes up the inequalities or roughness in the surface of the board. We have found that even so-called smooth boards do have inequalities or rough spots on the surface which are eliminated by the sealing iilm.

The drying of the coated board is accomplished with a low degree of heat, e. g. about F. to 200 F., the temperature depending upon the height of the'drying tower, which is preferably used. The coating, however, can bedried at room temperature, or by forced drying.

It will be appreciated that by simply running the cushion board throughan inexpensive coating material, the product obtained is much less costlythan treating the cushion board with a facing of Vinylite resin or other paper facings, such as gloss papers, particularly where such resins or papers are applied to both sides of the board.

Instead of a dipping procedure, theboard may v 3 I be coated on an intaglio coating machine which applies the coating material by means of wire wound rods serving to brush the coating on the board in a uniform manner. The board is passed through a tunnel drier whence it goes on a rewinding roll in the dry condition.

The sealing film preferably comprises resin, a wax, and clay in finely divided state. In some cases, the clay may be omitted. The resin is in greater amount than the wax, while the clay is in greater amount than either the resin or` wax. The material is dissolved or suspended in a suitable solvent which is evaporated off in the drying, and the dried and coated board is then rewound. l

A preferred example employing resin, wax and clay is here illustrated:

The resin used is N-butyl methacrylate resin. The wax is pale yellow amorphoid wax 180 F. melting point, also referred to as a well reilned petrolatum wax. The clay is a kaolin clay of about 300 mesh fineness. A very ilne mesh is needed to keep the clay in suspension in the iinished coating. The solvent is an aromatic hydrocarbon solvent made by the Shell Oil Company.

The clay is thoroughly dispersed in the resin and wax by means. of a ball mili. This grinding takes a number of hours and is preferred to the colloidal mill since larger batches can be handled with relatively little labor. The solution or suspension will contain 43.75% of non-volatile solids and 56.25% of solvent.

Another preferred example illustrating a modiiication of proportions is the following:

Example B Grams N-butyl methacrylate resin 75 180 pale yellow wax 10 2220 solvent (Shell) 225 Clay (Dixie) 90 The wax is used for the purpose of increasing the melting point and providing a smoother finish as distinguished from a coating which lacks wax and which has a somewhat crystalline surface appearance. y

Any high melting point amorphoid or petroleum hydrocarbon wax can be used inplace of the pale'yellow wax, e. g., a white amorphoid Wax of 170 F. melting point. f

The solvent, of which many are commercially available, is essentially an aromatic hydrocarbon solvent, having an initial boiling point of not less than 145 F., and a dry point of not more than 300 F., with the flash point below 40 F.

In order to secure greater flexibility of the coating, suitable plasticizers may be added to the ingredients in the formulas, e. g., stearic acid.

In the accompanying drawing, we have illustrated the invention as applied to a crown cap, but it is to be understood as set forth above, that it is applicable to all forms of 'caps in which a cushion liner is utilized.

Referring to the drawings,

` with this invention:

Figure 2 is a sectional view of the coated board; and

Figure 3 is a view similar to Figure 1 in which thetcushion liner is provided with a center facing spo The cap of Figure 1 comprises a metal shell l0 having a skirt ii provided with the usual crimps i2. The cushion liner is indicated at i3 as a whole and includes the cellulosic board layer I 4 and films l5 and I 8 of one of the materials described above.` As stated, these films are deposited from a solution and are firmly adhered to one or both faces of the cellulosic layeril. In Figure 2 there is shown the coated board from which liners illustrated in Figures 1 and 3 are punched and assembled in the caps. Referring to Figure 3, there is employed a. center spot I1 which is adhered to the sealing nlm layer I5 without the need of an independent adhesive. The thermoplasticity of the lm I5 serves to tightly unite the spot to the film. It is not usually necessary to employ a center spot, but in some cases this may be desirable. The center spot may be of the customary paper, foil or cheml ical composition iilm material.

We claim:

1. A closure having a cushion liner therein of cellulosic material coated on at least one side with a coextensive, thermoplastic sealing film of N-butyl methacrylate resin, amorphoid wax land finely divided clay, the resin being present in greater amount than the wax and the clay being present in greateramount than the wax or resin.

2. A cushion liner for closures of cellulosic material coated on at least one side with a coextensive, thermoplastic sealing film of N-butyl methacrylate resin, amorphoid wax and i'lnely divided clay, the resin being present in greater amount than the wax and the clay being present in greater amount than the wax or resin.

ALBIN H. WARTH. PAUL GRABUS, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 748,586 Coddington Jan. 5, 1904 983,319 Smith et al. Feb. 5, 1911 1,123,206 Gaston Dec. 29, 1914 1,144,589 Fay June 29, 1915 1,215,737 Stahl Feb. 13, 1917 1,609,562 Lonsdale et al. Dec. 7, 1926 1,656,514 Warth Jan. 17. 1928 1,804,555 Gentile May 12, 1931 1,950,436 Williams Mar. 13, 1934 2,067,066 Schmidt et al Jan. 5, 1937 2,073,415 Enkur Mar. 9, 1937 2,091,180 Magill Aug. 24, 1937 2,097,754 Bradshaw Nov. 2, 1937 2,109,944 Larson Mar. 1, 1938 2,181,481 Gray Nov. 28, 1939 2,227,516 Soanes Jan. 7, 1941 2,232,595 Dittmar et al Feb. 18, 1941 2,275,063 Moore Mar. 3, 1942 2,290,392 Thomas July 2l, 1942 2,316,274 Mitchell Apr. 13, 1943 2,338,705' Costa et al. Jan. 11, 1944 2,341,925 Kulman Feb. 15, 1944 

